* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

:root {
    --primary-color: #4a90e2;
    --secondary-color: #2c3e50;
    --text-color: #333;
    --light-text: #fff;
    --background-opacity: 0.85;
    --transition-speed: 0.3s;
}

html, body {
    width: 100%;
    height: 100%;
    background-image: url(../pic/cat.jpg);
    background-size: cover;
    background-position: center center;
    background-attachment: fixed;
    color: var(--text-color);
}

.nav {
    height: 60px;
    width: 100%;
    color: var(--light-text);
    background-color: rgba(44, 62, 80, var(--background-opacity));
    display: flex;
    justify-content: center;
    align-items: center;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    position: fixed;
    top: 0;
    z-index: 1000;
}

.nav > img {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    margin: 5px 10px;
    transition: transform var(--transition-speed);
}

.nav > img:hover {
    transform: scale(1.1);
}

.nav > .space {
    flex: 1;
    max-width: 60%;
}

.nav > .blog-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin: 0 20px;
}

.nav > .nav-span {
    padding: 8px 16px;
    text-decoration: none;
    color: var(--light-text);
    border-radius: 4px;
    transition: background-color var(--transition-speed);
    margin: 0 10px;
}

.nav > .nav-span:hover {
    background-color: rgba(255, 255, 255, 0.1);
}

.container {
    width: 90%;
    max-width: 1200px;
    min-height: calc(100vh - 60px);
    margin: 80px auto 20px;
    display: flex;
    gap: 20px;
}

.container > .left {
    width: 280px;
    flex-shrink: 0;
}

.container > .right {
    flex: 1;
    background-color: rgba(255, 255, 255, 0.9);
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    overflow-y: auto;
}

.container > .left > .card {
    width: 100%;
    background-color: rgba(255, 255, 255, 0.9);
    padding: 25px;
    text-align: center;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.left > .card > img {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    margin-bottom: 15px;
    border: 3px solid var(--primary-color);
    transition: transform var(--transition-speed);
}

.left > .card > img:hover {
    transform: scale(1.05);
}

.left > .card > h3 {
    margin: 15px 0;
    color: var(--secondary-color);
}

.left > .card > a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color var(--transition-speed);
}

.left > .card > a:hover {
    color: var(--secondary-color);
}

.left > .card > .row {
    width: 100%;
    height: 40px;
    margin: 15px 0;
    display: flex;
    justify-content: center;
    gap: 20px;
}

.left > .card > .row > span {
    color: var(--secondary-color);
}

@media (max-width: 768px) {
    .container {
        flex-direction: column;
    }
    
    .container > .left {
        width: 100%;
    }
    
    .nav > .space {
        display: none;
    }
}